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<head>
<meta charset="utf-8"/>
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no, viewport-fit=cover"/>
<meta name="description" content="A diagram that shows a sheet of paper; nodes cannot be dragged or resized beyond the edge of the sheet."/> 
<link rel="stylesheet" href="../assets/css/style.css"/> 
<!-- Copyright 1998-2021 by Northwoods Software Corporation. -->
<title>A Single Page Diagram</title>
</head>

<body>
  <!-- This top nav is not part of the sample code -->
  <nav id="navTop" class="w-full z-30 top-0 text-white bg-nwoods-primary">
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          <h1 class="mb-0 p-1 ">GoJS</h1>
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  <div class="md:flex flex-col md:flex-row md:min-h-screen w-full max-w-screen-xl mx-auto">
    <div id="navSide" class="flex flex-col w-full md:w-48 text-gray-700 bg-white flex-shrink-0"></div>
    <!-- * * * * * * * * * * * * * -->
    <!-- Start of GoJS sample code -->
    
    <script src="../release/go.js"></script>
    <div class="p-4 w-full">
    <script id="code">
    function init() {
      var $ = go.GraphObject.make;

      var pageSize = new go.Size(612, 792);
      var pageMargin = new go.Margin(10);
      var usableMargin = new go.Margin(10);
      var pageBounds = new go.Rect(-usableMargin.left, -usableMargin.top, pageSize.width, pageSize.height);
      var usableArea = pageBounds.copy().subtractMargin(usableMargin);

      myDiagram =
        $(go.Diagram, "myDiagramDiv",
          {
            fixedBounds: pageBounds.copy().addMargin(pageMargin),
            initialAutoScale: go.Diagram.Uniform,
            "animationManager.isInitial": false,
            "undoManager.isEnabled": true,
            "draggingTool.isGridSnapEnabled": true,
            "resizingTool.doMouseMove": function() {
              var e = this.diagram.lastInput;
              e.documentPoint = limitPoint(e.documentPoint);
              e.viewPoint = this.diagram.transformDocToView(e.documentPoint);
              go.ResizingTool.prototype.doMouseMove.call(this);
            },
            "resizingTool.doMouseUp": function() {
              var e = this.diagram.lastInput;
              e.documentPoint = limitPoint(e.documentPoint);
              e.viewPoint = this.diagram.transformDocToView(e.documentPoint);
              go.ResizingTool.prototype.doMouseUp.call(this);
            },
            "TextEdited": function(e) {
              var node = e.subject.part;
              node.ensureBounds();  // has been resized, compute its new bounds
              var pt = limitPoint(node.location);
              node.location = stayInFixedArea(node, pt, pt);
            }
          });

      // the background Part showing the sheet of paper;
      // it has the fixed bounds of the diagram contents
      myDiagram.add(
        $(go.Part, "Grid",
          {
            layerName: "Grid",
            position: pageBounds.position,
            desiredSize: pageSize,
            isShadowed: true,
            background: "floralwhite"
          },
          $(go.Shape, "LineH", { stroke: "lightgray", strokeWidth: 0.5 }),
          $(go.Shape, "LineV", { stroke: "lightgray", strokeWidth: 0.5 })
        ));

      // This function is the Node.dragComputation, to limit the movement of the parts.
      function stayInFixedArea(part, pt, gridpt) {
        var diagram = part.diagram;
        if (diagram === null) return pt;
        // compute the document area without padding
        var v = usableArea;
        // get the bounds of the part being dragged
        var bnd = part.actualBounds;
        var loc = part.location;
        // now limit the location appropriately
        var l = v.x + (loc.x - bnd.x);
        var r = v.right - (bnd.right - loc.x);
        var t = v.y + (loc.y - bnd.y);
        var b = v.bottom - (bnd.bottom - loc.y);
        if (l <= gridpt.x && gridpt.x <= r && t <= gridpt.y && gridpt.y <= b) return gridpt;
        var p = gridpt.copy();
        if (diagram.toolManager.draggingTool.isGridSnapEnabled) {
          // find a location that is inside V but also keeps the part's bounds within V
          var cw = diagram.grid.gridCellSize.width;
          if (cw > 0) {
            while (p.x > r) p.x -= cw;
            while (p.x < l) p.x += cw;
          }
          var ch = diagram.grid.gridCellSize.height;
          if (ch > 0) {
            while (p.y > b) p.y -= ch;
            while (p.y < t) p.y += ch;
          }
          return p;
        } else {
          p.x = Math.max(l, Math.min(p.x, r));
          p.y = Math.max(t, Math.min(p.y, b));
          return p;
        }
      }

      function limitPoint(p) {
        return new go.Point(Math.max(usableArea.left, Math.min(p.x, usableArea.right)),
                            Math.max(usableArea.top, Math.min(p.y, usableArea.bottom)));
      }

      myDiagram.nodeTemplate =
        $(go.Node, "Auto",
          {
            resizable: true,  // but limited by overrides of ResizingTool methods, above
            dragComputation: stayInFixedArea  // this limits the DraggingTool
          },
          $(go.Shape,
            { fill: "white", portId: "", fromLinkable: true, toLinkable: true, cursor: "pointer" },
            new go.Binding("fill", "color")),
          $(go.TextBlock,
            { margin: 8, editable: true },
            new go.Binding("text").makeTwoWay())
        );

      myDiagram.linkTemplate =
        $(go.Link,
          { relinkableFrom: true, relinkableTo: true },
          $(go.Shape),
          $(go.Shape, { toArrow: "OpenTriangle" })
        );

      myDiagram.model = new go.GraphLinksModel(
      [
        { key: 1, text: "Alpha", color: "lightblue" },
        { key: 2, text: "Beta", color: "orange" },
        { key: 3, text: "Gamma", color: "lightgreen" },
        { key: 4, text: "Delta", color: "pink" }
      ],
      [
        { from: 1, to: 2 },
        { from: 1, to: 3 },
        { from: 2, to: 2 },
        { from: 3, to: 4 },
        { from: 4, to: 1 }
      ]);
    }
    window.addEventListener('DOMContentLoaded', init);
  </script>

  <div id="sample">
    <div id="myDiagramDiv" style="border: solid 1px black; width:100%; height:600px"></div>
    This pretends to show a sheet of paper with the diagram on it.
    Both the <a>DraggingTool</a> and the <a>ResizingTool</a> are constrained to keep the nodes within
    the area of the sheet of paper, minus the margins.
    The user can zoom and scroll/pan normally.
    There are several variables, such as <code>pageSize</code>, that govern how the diagram is set up.
  </div>
    </div>
    <!-- * * * * * * * * * * * * * -->
    <!--  End of GoJS sample code  -->
  </div>
</body>
<!--  This script is part of the gojs.net website, and is not needed to run the sample -->
<script src="../assets/js/goSamples.js"></script>
</html>
